The pressure at which typical gas distribution systems supply gas may vary according to the demands placed on the system, the climate, the source of supply, and/or other factors. However, most end-user facilities equipped with gas appliances such as furnaces, ovens, etc., require the gas to be delivered in accordance with a predetermined pressure, and at or below a maximum capacity of a gas regulator. Therefore, gas regulators are implemented into these distribution systems to ensure that the delivered gas meets the requirements of the end-user facilities. Conventional gas regulators generally include a closed-loop control actuator for sensing and controlling the pressure of the delivered gas.
In addition to a closed loop control, some conventional gas regulators include a relief valve. The relief valve is adapted to provide over pressure protection when the regulator or some other component of the fluid distribution system fails, for example. Accordingly, in the event the delivery pressure rises above a predetermined threshold pressure, the relief valve opens to vent at least a portion of the gas to the atmosphere, thereby reducing the pressure in the system.
FIG. 1 depicts one such conventional gas regulator 10. The regulator 10 generally comprises an actuator 12 and a regulator valve 14. The regulator valve 14 defines an inlet 16 for receiving gas from a gas distribution system, for example, and an outlet 18 for delivering gas to an end-user facility such as a factory, a restaurant, an apartment building, etc. having one or more appliances, for example.
The actuator 12 is coupled to the regulator valve 14 to ensure that the pressure at the outlet 18 of the regulator valve 14, i.e., the outlet pressure, is in accordance with a desired outlet or control pressure. The actuator 12 includes a housing 20 and a control assembly 22. The housing 20 defines a cavity 21 containing at least a portion of the control assembly 22. The control assembly 22 is adapted for sensing and regulating the outlet pressure of the regulator valve 14. Specifically, the control assembly 22 includes a diaphragm 24, a piston 32, and a control arm 26 having a valve disc 28. The control assembly 22, and more particularly, the diaphragm 24 senses the outlet pressure of the regulator valve 14 and adjusts a position of the valve disc 28 to control the flow of fluid through the regulator valve 14.
More particularly, the diaphragm 24 is operably coupled to the control arm 26, and therefore, the valve disc 28 via the piston 32, and controls the opening of the regulator valve 14 based on the sensed outlet pressure. For example, when an end user operates an appliance, such as a furnace, for example, that places a demand on the gas distribution system downstream of the regulator 10, the outlet flow increases, thereby decreasing the outlet pressure. Accordingly, the diaphragm 24 senses this decreased outlet pressure and moves the piston 32 and the right-side of the control arm 26 downward, relative to the orientation of FIG. 1. This displacement of the control arm 26 moves the valve disc 28 to open the regulator valve 14. So configured, the appliance may draw gas toward the outlet 18 of the regulator valve 14.
In the conventional regulator 10 depicted in FIG. 1, the control assembly 22 further functions as a relief valve, as mentioned above. Specifically, the control assembly 22 also includes a relief spring 40 and a relief valve 42. The relief valve 42 is disposed within a vent 34 formed integrally with the housing 20 of the actuator 12. The diaphragm 24 includes an opening 44 through a central portion thereof and the piston 32 includes a sealing cup 38. The relief spring 40 is disposed between the piston 32 and the diaphragm 24 to bias the diaphragm 24 against the sealing cup 38 to close the opening 44, during normal operation.
Upon the occurrence of a failure such as a break in the control arm 26, the control assembly 22 is no longer in direct control of the valve disc 28 and inlet flow through the regulator valve 14 will move the valve disc 28 move into an extreme open position. This allows a maximum amount of gas to flow into the actuator 12. Thus, as the gas fills the actuator 12, pressure builds against the diaphragm 24 forcing the diaphragm 24 away from the sealing cup 38, thereby exposing the opening 44. The gas therefore flows through the opening 44 in the diaphragm 24 and toward the relief valve 42.
The relief valve 42 includes a valve plug 46 and a release spring 54 biasing the valve plug 46 into a closed position, as depicted in FIG. 1. Upon the pressure within the actuator 12 and adjacent the relief valve 42 reaching a predetermined threshold pressure, the valve plug 46 displaces upward against the bias of the release spring 54 and opens, thereby exhausting gas into the atmosphere through the vent 34 and reducing the pressure in the regulator 10. In some embodiment, the vent 34 includes a plurality of internal threads 35 for being threadably connected to piping, to pipe the exhausted gas to a specific location.
Depending on the particular application of the regulator 10, the size of the vent 34 and the components of the relief valve 42 may vary. For example, applications requiring high capacity relief, may also require a higher capacity relief valve 42. High capacity relief valves are typically constructed similar to the relief valve 42 discussed above, with the exception that they are larger in size. Thus, the size of the vent 34 must also be increased to accommodate the larger relief valve.
FIG. 2 depicts an exterior of one conventional regulator housing 20 including a vent 34 configured to accommodate a low capacity relief valve, for example. The housing 20 includes an upper housing component 20a and a lower housing component 20b. The upper housing component 20a includes a shell portion 51 and an integrally defines the vent 34. The vent 34 includes a diameter, for example, of approximately 2 inches or less, for venting performance associated with the low capacity relief valve. Additionally, the upper and lower housing components 20a, 20b include flanges 25a, 25b extending around a perimeter thereof and which are secured together with a plurality of fasteners 36. The number and spacing of the fasteners 36 is dictated by the design of the regulator 10 such that the flanges 25a, 25b of the housing components 20a, 20b can effectively compress and seal the diaphragm 24 depicted in FIG. 1, thereby minimizing the opportunity for leakage and ensuring optimal operation. The fasteners 36 conventionally include threaded fasteners such as hexagonal bolts and nuts, as depicted.
The conventional housing components 20a, 20b are manufactured with a casting process, wherein a plurality of mold cores are positioned relative to one another to cooperatively define a mold cavity. The mold cavity defines the specific geometry of the housing components 20a, 20b. Due to the intricacies of casting, the upper housing component 20a of the conventional housing depicted in FIG. 20 is formed with a pedestal portion 31 directly between the vent 34 and the flange 25a. The pedestal portion 31 of the upper housing component 20a depicted in FIG. 2 is generally solid and disposed between a pair of adjacent fasteners 36. Not only is the solid pedestal portion 31 a product of the manufacturing process, but it can also provide structural support to the portion of the vent 34 disposed above the flange 25a of the upper housing component 20a. 
In contrast, FIG. 3 depicts a partial exterior view of another conventional upper housing component 120a including a vent 134 configured to accommodate a high capacity relief valve. Thus, the vent 134 has a larger diameter than the vent 34 depicted in FIGS. 1 and 2, for example. The vent 134 may include a diameter of approximately 2 and ½ inches or more, for venting performance associated with the high capacity relief valve. Similar to the housing 20 discussed above, the upper housing component 120a depicted in FIG. 3 includes a shell portion 151 and a flange 125a extending around the perimeter of the shell portion 151. The flange 125a is adapted to be secured to a flange of a lower housing component (as shown in FIG. 1, for example) with a plurality of threaded fasteners 136.
Due to the increased size of the vent 134, two of the fasteners 136a, 136b must be positioned approximately below the vent 134 to provide a sufficiently uniform seal against the diaphragm that is disposed between the housing components. Accordingly, the upper housing component 120a depicted in FIG. 3 does not include a solid pedestal, such as the pedestal portion 34 depicted in FIG. 2, but rather, a pair of fins 131a, 131b. The fins 131a, 131b enable access to the flange 125a of the upper housing component 120a directly below the vent 134 such that the threaded fasteners 136a, 136b may be installed to secure the housing components together. Additionally, as with the pedestal portion 31 described above with reference to FIG. 2, the fins 131a, 131b can provide structural support to the portion of the vent 134 disposed above the flange 125a of the upper housing component 120a. 
One shortcoming of the conventional designs of the upper housing components 20a, 120a is that the pedestal portion 31 and fins 131a, 131b tend to interfere with a technician tightening and/or loosening the threaded fasteners 36, 136a, 136b. For example, as depicted in FIG. 3, a technician may use a wrench or other similar tool to tighten or loosen the fasteners 36 while assembling or disassembling the regulator 10. The fins 131a, 131b can interfere with the free movement of the wrench and therefore it may take longer to tighten or loosen the fasteners 136a, 136b. 